Try pandoc!

Convert   from CommonMark Creole DocBook Haddock markup HTML LaTeX Man Markdown (pandoc) Markdown (GitHub-flavored) Markdown (PHP Markdown Extra) Markdown (strict) MediaWiki MultiMarkdown Muse Native (Pandoc AST) OPML Org Mode reStructuredText Txt2Tags Textile TikiWiki TWiki Vimwiki

to S5 AsciiDoc LaTeX Beamer CommonMark ConTeXt DocBook v4 DocBook v5 DokuWiki DZSlides dzslides Haddock markup HTML 4 HTML 5 ICML JSON LaTeX Man Ms Markdown (pandoc) Markdown (GitHub-flavored) Markdown (PHP Markdown Extra) Markdown (strict) MediaWiki MultiMarkdown Muse Native (Pandoc AST) OpenDocument OPML Org Mode Plain text reveal.js reStructuredText RTF Slideous Slidy Texinfo Textile ZimWiki